Not Applicable
1. Field of the Invention
The present invention relates to golf equipment and, more specifically, to an instrumented golf club system having the ability to make quantitative measurements of specific mechanical or physical properties of the golf club during a golf swing. Data descriptive of the measured properties is stored within a memory device provided in the instrumented golf club.
2. Description of the Related Art
Various data measuring and collecting devices and methods are used for analyzing a golf club during a golf swing. In a similar manner, the effectiveness of a golf ball impact with the golf club during the golf swing can be measured in terms of initial launch conditions. Such launch conditions include the initial velocity, launch angle, spin rate and spin axis of the golf ball. These launch conditions are determined principally by the velocity of a club head at impact and the loft and angle of a club face relative to the intended trajectory of the golf ball""s flight. There are two general methods for analyzing the golf club during a golf swing: visual analysis and quantitative variable analysis.
The method of analyzing a golf club during a golf swing using visual analysis typically is conducted by a golf instructor capable of visually discerning golf swing variables, and suggesting corrections in the golfer""s swing to provide improvement. However, not every golfer has ready access to professional golf instruction. The golfer also can diagnose certain swing faults using visual analysis methodology employing one or more cameras to record the golfer""s swing and comparing it to a model swing. Using various camera angles and slow motion play back, the actual swing motion can be reviewed and altered in subsequent swings.
On the other hand, quantitative variable analysis employs sensors to directly measure various mechanical or physical properties of the golf club during the swing motion. Sensors, such as strain gauges or accelerometers, typically are attached to the shaft or the golf club head. Data collected from these sensors then may be transferred to a signal processor via wires or radio waves, and can be presented in various graphical formats, including graphical and tabular charts. A significant drawback associated with the use of wires in an instrumented golf club is that the wires can be very cumbersome, and can become obtrusive to the golfer when the golfer attempts to swing the golf club. Several different approaches to analyzing a golf club or baseball bat during a baseball or golf swing using quantitative variable analysis are discussed in the patents listed below.
For example, in U.S. Pat. No. 4,759,219, issued to Cobb et al., the specification discloses a baseball bat with a self-contained measuring device and display. A spring potentiometer is used to measure centrifugal force, and an LED or LCD displays the measured force. However, this bat does not contain any data storage capability.
U.S. Pat. No. 5,233,544, issued to Kobayashi, discloses a golf club having multiple sensors, and a cable for transmitting data to a computer for data processing. This arrangement can accommodate up to 5 sensors in a cartridge located in the handle region of the golf club.
U.S. Pat. No. 3,182,508, issued to Varju, discloses the use of a strain gauge in the bottom of a golf club, and a wire for connecting the sensor to a data processing means located separate from the golf club.
U.S. Pat. No. 5,694,340, issued to Kim, discloses the use of multiple sensors for measuring the acceleration of a golf club, and uses either a cable or radio transmissions to transfer data from the sensors to an external data processing means.
U.S. Pat. No. 4,991,850, issued to Wilhelm, discloses the use of a sensor for measuring the applied force of a golf swing. The sensor data can be displayed on a wrist-mounted arrangement or be downloaded to a computer via cable or radio transmission.
U.S. Pat. No. 3,792,863, issued to Evans, discloses the use of multiple sensors, including an accelerometer and strain gauges, to measure torque and flex. Data is transferred from the golf club to a data analysis station via FM radio signals, with each sensor having its own data transfer frequency.
Thus, data transfer to an external memory device is a significant drawback. The cumbersome nature of data transfer via cables or wires affects the motion and feel of a golfer""s actual golf swing. In addition, while the use of radio transmissions is preferable to the use of wires or cables emanating from the golf club for transferring data, a transmitter adds excessive weight. The effective range of these wireless instrumented golf clubs is limited by the low power used in such embodiments, and the accuracy of the radio transmitted data is subject to interference or noise from other sources of nearby radio transmissions.
Furthermore, in conventional systems, the receiving equipment typically must be located in close proximity to the radio transmitter disposed in the golf club thereby restricting the flexibility and portability of using such systems. Thus, it is desirable to provide an instrumented golf club that approximates the weight, balance and feel of a golfer""s own golf club, in order to ensure that the data collected from the instrumented golf club is applicable to the golfer""s actual golf swing. It also may be desirable to provide additional sensors for measuring certain parameters of a golf swing that have previously not been available in instrumented golf clubs. It further may be desirable to provide an efficient means of memory storage within the instrumented golf club to enable internal data capture and storage until the user is ready to download the data for further processing. It further may be desirable to provide data from the instrumented golf club for golf club design.
The instrumented golf club system of the present invention comprises an internally powered and instrumented golf club with multiple sensors to measure, store, and provide an external display of quantitative variables of a golf club during a golf swing. A distinctive feature of the instrumented golf club of the present invention is the use of a data storage memory device located within the instrumented golf club. This eliminates the need to use radio transmission hardware, data cables or wires to transfer data to an external data processing means. This also allows a golfer to swing the instrumented golf club without getting entangled in cables or wires, thus better allowing the golfer to replicate his or her natural golf swing.
In a preferred embodiment, a loop memory device, or ring buffer memory device, is used to continuously store measured data. New data replaces older data in the ring buffer during each successive cycle. The use of a ring buffer memory device is preferable for the creation of an instrumented golf club that is lightweight and free of cables or radio transmitters. Using a linear data capture approach, as taught by the prior art, would require extensive amounts of memory, and would make it very difficult to provide such memory requirements completely internal to an instrumented golf club. It is through the use of the ring buffer memory that one is able to efficiently capture the desired swing data of interest, such as impact with a golf ball, and eliminate the need to provide internal memory to capture data unrelated to a golfer""s swings.
Furthermore, since the ring buffer memory captures only the desired swing data of interest, data for multiple swings can be stored in the memory device of the instrumented golf club of the present invention. This provides increased flexibility and mobility to the user since the user is not required to stay within close physical proximity to the external data processing means.
Incorporating an internal power source for the instrumented golf club of the present invention is preferred for providing the benefits of flexibility and mobility. Location of the internal power source also can be used to provide a proper weight balance, or swing weight, for the instrumented golf club, thereby closely approximating the golfer""s own golf club. Although the internal power source can be placed in various locations within the instrumented golf club, in a preferred embodiment, a battery tube and one or more batteries are located within the shaft.
Furthermore, the rotation rate about a predefined coordinate system of any desired point on or inside the instrumented golf club can be measured directly by an angular rate sensor. Use of an angular rate sensor provides accurate data for measuring the specific rotation rate of an instrumented golf club. In the prior art, instrumented golf clubs used a combination of sensors to formulate an indirect measurement of rotation rate, which resulted in imprecise measurements. Thus, due to the importance of accurately measuring this particular swing variable, it is desirable to provide a means of capturing accurate angular rotation rate data.
The instrumented golf club system of the present invention further comprises an external data processing means and an interface means to provide communication between the instrumented golf club and the external data processing means, or computing means. Quantitative swing data can be captured, transferred to the processing means, and then presented in any number of graphical, tabular or other visual formats to provide a golfer with meaningful feedback regarding the dynamics of a golf swing.
In addition, the instrumented golf club system of the present invention can be used as a design tool for golf clubs including investigation of such variables as club head geometry, shaft dynamics, structural material behavior and type and location of weighting materials. As an example, the effect of different club head weighting locations can be measured for a wide range of golf swings to provide improved performance within this range of swings.
Accordingly, it is an object of the present invention to provide an instrumented golf club capable of measuring and storing data within the instrumented golf club without the use of an intermediate conduit such as external data transfer cables, wires or radio transmissions, thereby allowing greater flexibility and mobility to a user of the instrumented golf club.
Having briefly described the present invention, the above and further objects, features and advantages thereof will be recognized by those skilled in the pertinent art from the following detailed description of the invention when taken in conjunction with the accompanying drawings.